If you're setting out to clear the map, Diablo 4 Altar of Lilith statues will be one of your biggest collection tasks. Each one rewards some Diablo 4 renown and also unlocks stat bonuses for all your future characters in the same realm.
Every Altar of Lilith can be found in the overworld, so don't worry about seeking them out inside dungeons. These statues aren't marked on the map until you unlock them though. Some are pretty easy to find alongside the edge of paths, but others are a bit tricky to spot despite their red glow.